Lead-containing solder is used for joining of a terminal and a conductor (power supply member) that is formed on the surface of a glass plate in uses involving the windshield of an automobile. In recent years, lead-free solder has come to be desired for the purposes of, among other things, reduction of the load on the environment.
However, lead-free solder has not been employed broadly because it uses, as materials to replace lead, indium, tin, silver, etc. which are expensive. On the other hand, there is a proposal that instead of lead-free solder, conductive rubber, for example, be used as a means for joining a conductor and a terminal (see, e.g., Patent document 1, for example). Conductive rubber establishes an electric connection between a conductor and a terminal in such a manner that it is kept in a compressed state.